Quick cycle biopsy system

ABSTRACT

A method for extracting a tissue sample includes altering the pressure inside the lumen of a cannula to facilitate extraction of a tissue sample from the cannula. One aspect of the invention includes a biopsy apparatus comprising a valve for controlling the pressure inside the lumen of the cannula. In one variation, the pressure/vacuum generating device is connected to a cannula with a closed distal end and an orifice located on a circumferential surface of said cannula. A cutting sheath is slidably disposed over said cannula. The valve may be provided between the pressure/vacuum generating device and the cannula to control the pressure within the lumen of the cannula.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation of prior application Ser. No. 11/047,953, filedJan. 31, 2005 now U.S. Pat. No. 7,517,321, the entirety of which ishereby incorporated by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO A COMPACT DISK APPENDIX

Not applicable.

BACKGROUND OF THE INVENTION

Various biopsy devices for taking tissues samples have been previouslydisclosed. Typically, the device comprises a hand piece, in which aportion of a hollow biopsy cannula/needle protruding from the hand pieceis introduced with its sampling chamber into the tissue beinginvestigated. A sample of the tissue is sucked into the sampling chamberby vacuum, separated by a sample separating mechanism, and then removed.

Examples of biopsy devices are disclosed in British Patent PublicationNo. GB 2018601A, European Patent Publication No. EP 0890 339 A1, U.S.Pat. No. 5,526,822, German Patent No. DE 40 41 614 C1, InternationalPublication No. WO 96/28097, German Patent Publication No. DE 100 34 297A1, International Publication No. WO 98/25522, and US Patent PublicationNo. 2001/0011156 A1, each of which is incorporated herein by referencein its entirety.

Integrated biopsy systems having built-in actuators for displacing abiopsy cannula and a corresponding cutting sheath and a pressure/vacuumgenerating device for suctioning and expelling tissue samples form thelumen of the cannula are described in U.S. patent application Ser. No.10/500,518, entitled “BIOPSY DEVICE AND INSERTABLE BIOPSY NEEDLE MODULE”filed Jun. 29, 2004, and U.S. patent application Ser. No. 10/500,522,entitled “BIOPSY DEVICE FOR REMOVING TISSUE SPECIMENS USING A VACUUM”filed Jun. 29, 2004, each of which is incorporated herein by referencein its entirety.

Although various biopsy devices have been previously disclosed, it maybe desirable to improve the reliability and efficiency of the presentbiopsy devices such that extraction and/or removal of the tissue samplefrom the tissues sample chamber within the biopsy cannula may befacilitated.

BRIEF SUMMARY OF THE INVENTION

One aspect of the invention comprises a method for facilitating theejection/removal of a tissue sample from the tissue chamber within thebiopsy cannula. The cannula may be inserted into a body of tissue withina patient to extract a sample of the tissue of interest. Once the sampletissue is pulled within the tissue chamber in the cannula throughsuction, the chamber is closed, severing the sample tissue from thepatient's body. The cannula may then be removed from the patient's body.The tissue chamber is maintained in a closed position while the lumen ofthe cannula is pressurized. Once the pressure within the lumen of thecannula has reached a desired level, the tissue chamber is opened. Thepressure behind the sample tissue will force the sample tissue to ejector move out of the tissue chamber. The operator may open only a distalportion of the chamber (e.g., exposing only the distal one-third orone-half of the chamber opening) to prevent the fluids from leakingthrough the side of the sample tissue, and force the sample tissue toexit from the partial opening. Alternatively, if the pressure is highenough, the operator may open the chamber completely.

Another aspect of the invention comprises a biopsy apparatus with anintegrated valve for facilitating high and/or low pressure build-upwithin a pressure chamber for providing suction and/or ejection pressureto the lumen of the biopsy cannula. In one variation, the biopsyapparatus comprises a built-in pressure generator that is coupled to theproximal end of a biopsy cannula. The pressure generator may be capableof generating both a positive and a negative (e.g., vacuum) pressurewithin the lumen of the cannula. A valve is placed between the biopsycannula and the pressure generator to control the fluid flow from thechamber of the pressure generator to the lumen of the biopsy cannula. Anelectronic system control board coupled to an actuator may be utilizedto displace the biopsy cannula and its corresponding cutting sheath. Theelectronic system control board may also be adapted to control thepressure generator and the valve. In one application, the valve isplaced in the open position when the pressure generator applies suctionto the lumen of the cannula to extract a sample of the interested tissueinto the chamber of the cannula. After the chamber is closed and thecannula is removed from the patient's body, the valve is closed and apositive pressure is built-up within the chamber of the pressuregenerating device. Once the tissue chamber has been opened, the valvemay subsequently be opened to release the built-up pressure into thelumen of the cannula. The fluid inside the pressure chamber enters thelumen of the cannula and ejects the tissue sample out of the cannula.One of ordinary skill in the art having the benefit of the disclosureherein would appreciate that the valve may be utilized to build-upeither positive or negative pressure inside the chamber to variouspressure levels as desired by the operator. The valve may then bereleased to cause a sudden increase or decrease in pressure within thelumen of the cannula.

These and other embodiments, features and advantages of the presentinvention will become more apparent to those skilled in the art whentaken with reference to the following more detailed description of theinvention in conjunction with the accompanying drawings that are firstbriefly described.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a cross-sectional view of a variation of a biopsy apparatuswhere the biopsy cannula is connected to a pressure generating device.

FIG. 1B is a perspective view of the distal portion of the biopsycannula of FIG. 1A. The cutting sheath is shown in a retracted positionexposing the tissue chamber in the lumen of the biopsy cannula.

FIG. 1C illustrates the distal portion of the biopsy apparatus of FIG.1A with the cutting sheath advanced over the tissue chamber.

FIG. 2 illustrates a biopsy apparatus integrated within a housing withactuators for moving the biopsy cannula and its corresponding cuttingsheath.

FIG. 3 illustrates another variation of a biopsy apparatus with anintegrated valve for controlling fluid flow from the pressure generatorto the lumen of the biopsy cannula.

FIG. 4 is a diagram illustrating yet another variation of the biopsyapparatus where a bifurcating valve system is utilized to controlpressure distribution within the apparatus.

FIG. 5A shows another variation of a biopsy apparatus with its housingcover opened (perspective view).

FIG. 5B shows a partially disassembled biopsy apparatus of FIG. 5A. Theprimary components are fixed to a housing (shown without the housingcover) and the replaceable biopsy unit is shown separated from the mainhousing (perspective view).

FIG. 5C shows a lengthwise section of the biopsy apparatus of FIG. 5A.

FIG. 5D shows the base block of the biopsy apparatus of FIG. 5A(perspective view).

FIG. 5E shows the main housing/frame of the biopsy apparatus of FIG. 5Awith its corresponding actuator/driver and spring-load displacementsystem. The components are shown without the housing cover, and with thespring-load displacement system in an uncocked condition.

FIG. 5F is a cross-sectional view of the biopsy cannula and itscorresponding cutting sleeve of the biopsy apparatus of FIG. 5A. Thecannula is shown with its tissue sample chamber partially opened.

FIG. 5G illustrates the biopsy cannula carrier with press-fitted biopsycannula/cutting sheath and plastic holder (perspective view).

FIG. 5H shows the pressure generating device integrated with the biopsycannula carrier and installed on the main housing (perspective view).

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description should be read with reference to thedrawings, in which identical reference numbers refer to like elementsthroughout the different figures. The drawings, which are notnecessarily to scale, depict selected embodiments and are not intendedto limit the scope of the invention. The detailed descriptionillustrates by way of example, not by way of limitation, the principlesof the invention. This description will clearly enable one skilled inthe art to make and use the invention, and describes severalembodiments, adaptations, variations, alternatives and uses of theinvention, including what is presently believed to be the best mode ofcarrying out the invention.

Before describing the present invention, it is to be understood thatunless otherwise indicated, this invention need not be limited toapplications in humans. As one of ordinary skill in the art wouldappreciate, variations of the invention may be applied to various otheranimals and plants as well. Moreover, it should be understood thatembodiments of the present invention may be applied in combination withvarious imaging devices (e.g., ultrasound, X-ray, etc.) for guiding thesurgeon on the placement of the biopsy needle/cannula within a patient'sbody.

Taking biopsy of a tumor tissue is used herein as an example applicationof the biopsy apparatus and method disclosed herein. In light of thedisclosure herein, one of ordinary skill in the art would appreciatethat variations of the apparatus and/or method may be applicable forextracting samples from various types of tissues within the human body.

It must also be noted that, as used in this specification and theappended claims, the singular forms “a,” “an” and “the” include pluralreferents unless the context clearly dictates otherwise. Thus, forexample, the term “an actuator” is intended to mean a single actuator ora combination of actuators, “a fluid” is intended to mean one or morefluids, or a mixture thereof. Furthermore, the words “proximal” and“distal” refer to directions closer to and away from, respectively, aphysician operating the biopsy cannula, with the tip end (i.e., distalend) placed inside the patient's body. Thus, for example, the cannulaend placed in the tissue of the patient would be the distal end of thecannula, while the cannula end outside the patient's body would be theproximal end of the cannula.

One aspect of the invention comprises a method of building up a pressureinside the biopsy apparatus to eject a tissue sample captured in thechamber of the device. In one variation, the method comprises providinga biopsy cannula having a closed distal end and an orifice located on acircumferential surface of said cannula. An example of such a biopsyapparatus 201 is shown in FIG. 1A. The orifice 202 on thecircumferential surface of the cannula forms the opening for access of atissue chamber 71 at the distal end of the lumen 203 of the cannula 2,as shown in FIG. 1A. A cutting sheath 3 is slidably disposed on thecannula 2. The cannula 2 with orifice 202 covered by the sheath 3, asshown in FIG. 1C, can be inserted into a body of tissue inside apatient. A needle or cannula guide may be first inserted into the tissueto guide the insertion of the biopsy cannula. A mechanical displacementmechanism, such as spring loaded lever or driver, may be used to ejectand/or force the biopsy cannula 2 and its corresponding cutting sheath 3into the desired body of tissue. A negative pressure (pressure lowerthan either tissue surrounding the cannula and/or the atmosphericpressure) is generated inside the lumen of the cannula. The negativepressure may be generated prior, during and/or after the insertion ofthe cannula/sheath unit into the tissue of interest.

Once the distal end 204 of the cannula 2 is in place, the cutting sheath3 may be retracted toward the proximal end of the cannula to expose theorifice 202. A suction draws a portion of the desired tissue into thetissue chamber 71 within the lumen of the cannula 2. In one particulardesign, a stopper 79 is positioned within the lumen 203 of the cannula2, proximal to the orifice on the cannula. The distal end of the stopperalong with the wall of the cannula lumen forms a tissue chamber 71 atthe distal portion of the cannula. The stopper 79 partially blocks thelumen to allow fluid flow in the unobstructed portion 205 of the lumen,but to prevent the captured tissue sample from migrating in the proximaldirection. Once the tissue is captured within the tissue chamber 71, thecutting sheath 3 may be advanced in a distal direction to cover theorifice 202 on the cannula 2, which acts to sever the sample tissue fromthe body of tumor tissue in the patient. The distal tip 72 of thecutting sheath 3 may be advanced past the distal edge 206 of the tissuechamber to achieve a clean separation between the sample tissue and theprimary body of tissue of interest. The cannula 2 and its correspondingcutting sheath 3 may then be removed from the patient's body.

While the cutting sheath is closed, a positive pressure (a pressurehigher than atmospheric pressure) is generated within the lumen 203 ofthe cannula 2. As shown in FIG. 1A, a pressure generator 207, such as acylinder with a single piston, may be utilized to generate the negativeand positive pressure within the lumen 203 of the cannula 2. In theparticular example shown in FIG. 1A, to release the negative pressureinside the lumen of the cannula, the piston 210 may be retracted pastthe release port 208 such that the pressure within the lumen 203 of thecannula 2 and the pressure chamber 209 of the pressure generator cannormalize. The piston 210 may then be advanced in the distal directionto compress air in the lumen 203 of the cannula 2. Once the positivepressure within the lumen 203 reaches a predefined level (e.g., thepiston has been advanced a predefined distance; a pressure sensor isutilized to verify the pressure inside the lumen, etc.), the cuttingsheath 3 is retracted in a proximal direction to expose the tissuesample within the tissue chamber 71. One may open the chamber 71 inincrements. For example, one may initially open the chamber 71 only thedistal one-third or one-half thereof. Alternatively, one may fully openthe chamber at once. The pressure that has built-up behind the tissuesample will force the tissues sample to eject out of the tissue chamber71.

Referring to FIG. 2, a variation of the biopsy apparatus is shown with ahousing 211 and integrated actuators/drivers 212 for displacing thecannula 2, the corresponding cutting sheath 3, and the piston 210. Aspring-loading mechanism or other similar ejector may be implemented forthe insertion of the biopsy cannula 2 and its corresponding cuttingsheath 3. An electronic controller board with an on-board processor maybe utilized to control and synchronize the action of all the associatedactuator and displacement mechanisms in the integrated biopsy apparatus.An optional needle/cannula guide 213 may be utilized to guide theinsertion of the cannula/sheath unit. One of ordinary skill in the artwould appreciate that other pressure/vacuum generating devices may alsobe implemented in place of the cylinder/piston unit.

By changing the program control parameters in an integrated biopsydevice, such as the one shown in FIG. 2, air pressure can be accumulatedand released all at once instead of in a gradual manner. For example,before the chamber is opened, the controller may depress the pistonwithin the cylinder by a predetermined distance to generate a positivepressure and hold the piston in place to maintain the pressure.Thereafter, the tissue chamber is exposed by sliding open the chambercover (i.e., cutting sheath). As soon as the tissue sample fits throughthe opening space, it will shoot out of the biopsy cannula. In theparticular design shown in FIG. 2, because the lumen opening 214 fordelivering the pressure is at the proximal end of the tissue chamber 71close to the base 215 of the chamber, opening of the chamber cover atthe distal end 216 first may prevent premature leakage of the fluidpressure and allow the fluid pressure to push the captured sample allthe way through the chamber, and in the process clear the chamber of anyparticles.

In another aspect of the invention, as shown in FIG. 3, a valve 218 isimplemented to allow positive or negative pressure to build-up with thepressure generation device 207 such that instant pressure increase ordecrease can be realized with the release/opening of the valve 218.Alternatively, a large positive or negative pressure may be createdwithin the pressure chamber 209 of the pressure generating device 207,and the valve 218 may be utilized to control the release of thepositive/negative pressure into the lumen of the cannula 2. In addition,a seal (e.g., O-ring) 219 may be placed between the cannula and itscorresponding cutting sheath to prevent the leakage of negative pressurethat has been generated in the surrounding tissue when the tissuechamber 71 is opened inside the patient's body. An additional seal(e.g., O-ring) 220 may also be provided between the cannula guide 213and the cutting sheath 3.

In one example application, with the assistance of an ultrasound imagingdevice, a cannula guide 213 is inserted into a body of tumor tissuewithin the patient's body. The cannula 2 with its tissue chamber 71covered and placed in a spring-loaded cocked position is inserted intothe cannula guide and advanced toward the tissue. The spring-loadedcannula is then released, shooting into the tumor tissue. With thecannula 2 in place, the piston 210 in the pressure generating device 207is retracted to regenerate a negative pressure within the lumen of thecannula 2. The cutting sheath is subsequently retracted to expose theorifice to the tissue chamber. A sample of the tissue is suctioned intothe tissue chamber 71. A delay may be built into the control protocol toensure that the tissue chamber 71 is loaded before the cutting sheath 3is slid back into the closed position. In an alternative approach, thevalve may be closed and a negative pressure generated within the chamber209 of the pressure generating device 207 prior to or after the cuttingsheath is retracted and the chamber is opened. With the cannula 2inserted inside the tumor tissue and the orifice to the tissue chamberin an open position, the valve 218 may be opened to provide the suctionto capture a sample of the tumor tissue within the tissue chamber.

Once the sample of tissue is suctioned into the tissue chamber 71, thecutting sheath 3 is advanced forward of the orifice of the tissuechamber 71, severing the sample tissue in the chamber from the body oftumor tissue. With the sample tissue secured in the tissue samplechamber 71, both the cannula 2 and the cutting sheath 3 are withdrawnfrom the patient's body. Either prior to, during, or after the cuttingsheath 3 is retracted to expose the captured tissue sample, the valve218 may be closed and positive pressure generated in the pressurechamber 209 inside the pressure generating device 209 by compressing thepiston 210. With the cutting sheath 3 retracted and the orifice of thetissue sample chamber 71 at least partially exposed, the valve 218 maythen be released to direct a positive pressure into the lumen 203 of thecannula 2 to force the sample tissue out the cannula 2. The stepsdescribed above may be executed through manual control, or may beprogrammed into an electronic controller that is linked with theactuators/drives to synchronize the various components and carryout thedesired procedure.

FIG. 4 illustrates another valve implementation to control pressurebuild-up and release within a pressure chamber. In this configuration, abifurcate 221 with two valves 222, 223 are provided between the pressuregenerating device 209 and the biopsy cannula 2. A first valve 222, whichis inline with the cannula 2 and the pressure generating device 207,controls the release of pressure into the lumen of the cannula 2. Asecond valve 223 on the bifurcating branch is provided for releasingpressure from the system or allowing inflow of air into the pressurechamber 209. The valves 222, 223 may be coupled to actuators that arelinked to an electronic system controller.

A particular variation of a biopsy apparatus is illustrated in FIG. 5A.Integrated in a housing interior of a hand piece 1 are all devices andcomponents required to perform a vacuum biopsy (FIG. 5A), so that nocables or lines are required going from the housing of the hand piece toother external supply devices. Thus, the hand piece 1 constitutes acomplete vacuum biopsy apparatus, which is freely moveable in alldirections. The apparatus is shown with an optional valve 150 forcontrolling the fluid flow from the vacuum/pressure generating unit 5,through the connection element 4, to the proximal end of the biopsycannula. The valve may further comprise a control knob 151 to allow theoperator to manually open the valve and release the pressure inside thepressure chamber of the vacuum/pressure generating unit 5.Alternatively, the valve 150 may be coupled to an actuator, which islinked to an electronic system control board. The electronic systemcontrol board may open and close the valve through controlling theactuator. The actuator may be positioned below the base board withlevers or other mechanical interface 152 (FIG. 5B), extending above thebase board, for coupling with the valve mechanisms. One of ordinaryskill in the art, having the benefit of this disclosure, wouldappreciate that other fluid flow control mechanisms may be implementedin place of the valve to control positive and/or negative pressurebuild-up inside the pressure chamber of the vacuum/pressure generatingunit 5.

In applications where pressure build-up is regulated by keeping thetissue chamber closed during pressurizing and depressurizing of thepressure generating device, the apparatus 1 may be fabricated withoutthe control valve 150, and the connection element 4 may be directlyconnected to the pressure generating device 5.

From the distal part of the distal end cover 6 protrudes the distal partof the hollow biopsy cannula 2, with the cutting sheath 3 surrounding itcoaxially, which is required to remove the tissue sample. Usually, acoaxial cannula guide is placed into the tissue first, into which thebiopsy cannula 2 with cutting sheath 3 is inserted. Outside the proximalend cover 7 of the housing there is arranged a connection element 4(e.g., a transparent flexible hose) which connects the valve and thevacuum pressure generating device 5, arranged in parallel with thebiopsy cannula, to the interior cavity of the biopsy cannula 2. Thehollow connection element 4 is situated in immediate proximity to theend cover 7 of the housing. The biopsy cannula with cutting sheath andadditional elements, arranged in a biopsy cannula carrier 37, formstogether with the connection element 4 and the vacuum pressuregenerating device 5 an element 20, easily inserted or taken out at thetop, which is replaced as necessary (FIG. 5B). The housing cover 10 isopened for this purpose. As FIG. 5B in particular shows, the biopsydevice can be divided into parts which are firmly connected to thehousing (disinfected parts) and a removable element 20 (sterile part).While the parts firmly connected to the housing are merely disinfected,the removable element 20 may come in a sterile package and can bereplaced as necessary, especially for each new patient.

The removable insert element 20, comprising a vacuum pressure generatingdevice 5, elastic connection element, biopsy cannula carrier 37 withcannula and cutting sheath and additional elements connected to it, alsocontains a guide roller 81 mounted on the cannula. This unit, includingan insert aid, comes in a sterile package. The plunger in the syringebody of the vacuum/pressure generating unit 5 comes slightly (about 1-2mm) displaced from the syringe bottom and the sample removal chamber 71of the biopsy cannula 2 may be open to improve sterilization within thechamber. After opening the housing cover 10, the carrier element 37,including biopsy cannula 2, cutting mechanism 3, and other partsconnected with it, such as the vacuum pressure generating device 5hooked up to the connection element 4, is inserted into the connectionelement provided for this (FIG. 5B). FIG. 5G shows the biopsy cannulacarrier from the under side with the components, for coupling the biopsycannula 2 and the cutting sheath 3 to the gear motor 21, exposed.

During the insertion process, the operator should check to ensure thatthe gear 74 engages with the teeth of the toothed roller 23; that thecutting sheath is inserted from above into the U-shaped holder 36, andat the same time that the brackets 40 of the tension slide areintroduced into the recesses 77 of the carrier element; the guide roller81 is inserted in the passage 13, so that the flanks 101 and 102 embracethe distal end cover 6. The cutting sheath 3 is mounted in the guideroller 81, able to move lengthwise and turn freely; the guide roller 81itself, however, can no longer move relative to the cutting sheath 3after being inserted in the distal end cover 6, as illustrated in FIG.5B. The vacuum pressure generating device 5 is then inserted onto thebase block 8, with its connection piece 63 inserted into the U-shaped,upward-open passage 16 on the base block 8. The connection piece 63 liesabove the switch pin 19.

When the housing cover is closed, the connection piece 63 is forceddownward and activates the miniature switch by the switch pin 19 builtinto the end cover of the housing. This activates the electrical controlsystem, which is indicated by blinking of the reset diode on the controlpanel located at the left side 113 of the hand piece 1. The reset diodeat first blinks yellow, which means that the positioning of theindividual elements, i.e., the inserting process, is not yet finished;the DC gear motor 21 first open the sample chamber 71 all the way (atwhich point the motor feels resistance and calibrate that point), itthen rotates the other direction a certain predetermined number ofrevolutions until the sample chamber 71 is closed with the cuttingsheath 3. This occurs by twisting the threaded casing connected to thecuffing sheath. The cutting sheath moves in the distal direction untilthe gear 74 comes to bear against the inside of the holder 36. In onevariation, the controller is able to calibrate the displacement bycounting the number of the rotation during the reset sequence, and thenuses that information to start and stop the rotation rather than relyingon the physical stops. After closing the sample removal chamber, theplastic disk 78 bears against the holder 36 (inside). During thisprocess, or before or after it, the DC gear motor 58 brings the syringeplunger to bear against the syringe bottom. FIG. 5H shows the removableinsert element 20 inserted on the main housing frame 153.

After the starting positions have been established for the vacuumpressure generating device and the biopsy cannula/cutting sheath, thecocking diode lights up yellow and the sample removal diode light upgreen and the reset diode goes out. The operator must now decide whetherto initiate the cocking of the tension slide or to remove an additionalsample, e.g., because he has already previously removed one tissuesample. If the operator presses the cocking button, the cocking of thetension slide is initiated; the cocking diode blinks yellow, the piercediode blinks green, and the sample removal diode goes out. By pressingthe cocking button, the electrical DC gear motor 21 receives current andthe DC gear motor actuates the toothed roller 23. The gear 74 meshingwith the toothed roller 23 turns the spindle shaft and at the same timethe cutting sheath 3 connected to it. Since the spindle nut 75 ispress-fitted in the biopsy cannula carrier 37 and the gear 74 issupported against the holder 36, which is firmly connected to thehousing by the base block 8, the turning of the threaded spindle casing73 has the effect of moving the biopsy cannula carrier in the proximaldirection.

At the same time, the biopsy cannula 2 connected to the biopsy cannulacarrier by the bearing element 49 is carried along, resulting in the tipof the biopsy cannula moving into the cutting sheath. The biopsy cannulacarrier 37 is displaced in the proximal direction by the recess/bracketconnection of the tension slide against the action of the spiral spring31 until the lever of the locking element is forced into the recess ofthe tension slide by the spring. The tension slide is locked in thisposition. The gear motor receives the control command that the lockingposition has been reached, e.g., via a photocell installed in thesliding surface of the cover plate or based on the number of rotationsby the motor, which interacts with the retracted biopsy cannula carrier;the direction of turning of the motor is reversed and the cutting sheathis displaced in the proximal direction by the amount that the cuttingsheath had moved beyond the tip of the biopsy cannula by the movement ofthe tension slide and the biopsy cannula.

At the end of this step, the cutting sheath completely closes the sampleremoval chamber, as at the start of the cocking process. The lockingdiode lights up green; the blinking of the cocking diode goes out. Now,the biopsy cannula of the biopsy mechanism is inserted, for example, ina previously mounted coaxial cannula. The proximal end of the mountedcoaxial cannula receives a seal, designed so that it seals off the spacebetween cutting sheath and cannula, on one hand, and allows an easyinsertion of the biopsy cannula with cutting sheath, on the other. Theseal ring prevents air from the outside getting sucked in through thespace between cannula and cutting sheath. The seal ring likewiseprevents fluid (cytological material) from escaping after the biopsycannula is introduced or inserted. Thus, the possibility of thedisinfected hand piece 1 getting dirty is nearly precluded; on the otherhand, the flank 101 of the sterile guide roller 81 prevents the sterilecannula from getting dirty by reason of the hand piece 1. The tip of thebiopsy cannula is brought up in the cannula to the tumor and, afterbeing correctly positioned, thrust into the tumor.

The shot is triggered by pressing the activation button on the controlinterface panel. This has the result of swiveling the double-arm leverabout the axis to release the tension slide. The tension slide is hurledin the distal direction by spring action. The sample removal diodelights up green and the cocking diode goes out. By operating the programbutton, the sample removal sequence is enabled; the sample removal diodeblinks green. At first, the DC gear motor 58 will activate the vacuumpressure generating device. The plunger of the vacuum pressuregenerating device is moved in the direction of the base block, i.e.,away from the bottom of the syringe, until it reaches a position justbefore clearing the ventilation borehole 67. The vacuum is generated inthe system. After reaching its end position, the system activates themotor 21, the cutting sheath which closes the sample removal chamber isopened via the gear/spindle drive. During the opening process, thepartial vacuum prevailing in the system sucks in the tissue and anycytological fluid (cytological material) into the sample removalchamber. Cytological fluid may also flow due to the vacuum in the biopsycannula cavity and the vacuum pressure generating device.

It has proven to be advantageous to direct the partial vacuum by thestopper 79 primarily at the lower region, the lower side, of the sampleremoval chamber, and the stopper 79 will prevent or impede tissue fromgetting into the biopsy hollow cannula. When the sample removal chamberis fully open—the tissue sample is accommodated in the sample removalchamber—the gear motor 21 is reversed and the sample removal chamber 71is closed. By turning the cutting sheath, the tissue is separated by thecutting edge 72 of the sheath 3 during the closing process. In order toreliably cut through the tissue filaments, it is advantageous to movethe cutting sheath 3 beyond the distal end of the sample removal chamber(around 2 mm). In order to accomplish this, it is only necessary toprogram accordingly the microprocessor where the control data is kept.Because of the special configuration of the sample removal chamber andthanks to the vacuum applied, the tissue sample is held in the chamberwithout torsion, so that the tissue sample is not twisted or turned bythe rotating and lengthwise moveable cutting sheath 3 which surroundsthe biopsy cannula on the outside, as described.

After the sample removal chamber is closed, the DC gear motor isactivated for the vacuum generating unit 5. The plunger is firstretracted far enough to clear the ventilation opening 67 (FIG. 5F).After the vacuum is dissipated in the system, the plunger travels towardthe vacuum bottom until the ventilation borehole 67 is again closed, inorder to prevent the outflow of bodily fluid (cytological fluid). Theblinking of the sample removal diode goes out. The ejection diode lightsup yellow. The biopsy cannula with closed sample chamber is extractedfrom the cannula guide.

After the removal of the biopsy unit and providing a vessel to receivethe tissue sample and fluid, the program button is again operated andthe ejection diode starts to blink. First, the DC gear motor 58 of thevacuum pressure generating device is activated while the sample removalchamber remains closed. The turning direction of the DC gear motor 58remains and the threaded spindle with plunger moves in the direction ofthe syringe bottom, so that now an excess pressure is created in thesystem. After this, the gear motor 21 of the cutting sheath is operatedto open the sample removal chamber roughly halfway. As soon as thesample fits through the opening it will shoot out of the biopsy chamber.

In a system with a built-in valve 150, an alternative approach may beused to eject the sample from the sample removal chamber. After theremoval of the biopsy unit from the patient, the actuator coupled to thevalve is activated to close the valve 150. With the valve 150 closed,the DC gear motor 58 of the vacuum pressure generating device isactivated. The turning direction of the DC gear motor 58 remains and thethreaded spindle 53 with plunger moves in the direction of the syringebottom, so that now an excess pressure is created in chamber of thepressure generating device. After this, the gear motor 21 of the cuttingsheath is operated to open the sample removal chamber roughly halfway.The actuator couple to the valve is activated to open the valve andrelease the pressure into the biopsy cannula, and force the sample outthe biopsy chamber 71.

With the release of the excess pressure build-up in the vacuum/pressuregenerating unit 5, the sample is forced out due to the a pressure pulseand ejects into a waiting laboratory vessel even when the sample removalchamber is halfway open, and at the same time the chamber of the vacuumpressure generating device, the biopsy cannula and the sample removalchamber is cleared of tissue particles and fluid. The ejection of thesample when the sample removal chamber is around halfway open is so thatthe ejection of the tissue sample is assured and the tissue sample doesnot fall back into the chamber as a result of premature dissipation ofthe excess pressure. The narrowing of the cavity of the biopsy cannulaby the stopper 79, which prevents or impedes tissue from getting intothe cavity of the biopsy cannula, proves to be especially advantageouswhen removing the sample, since the narrower cross section boosts theejection pressure. The best ejection results, therefore, may be achievedwith the sample removal chamber halfway open; i.e., the cutting sheathclears half of the sample removal chamber. The excess pressure alsoforces tissue fluid out of the sample removal chamber and cleans it.

In the example illustrated in FIG. 5A, the vacuum pressure generatingdevice is arranged in parallel with the biopsy cannula. However, thevacuum pressure generating device may also be arranged lying in the axisof the biopsy cannula or the hand piece; neither does it require its ownconnection element, if for example it is mounted directly on the end ofthe biopsy cannula.

The components of the exemplary device shown in FIG. 5A and FIG. 5B arenow described in further detail. The gear motor 21 for the cockingmechanism and the cutting sheath is located at the distal lower-leftportion of the housing interior, while the actuating mechanism 105 (FIG.5H) for the vacuum pressure generating device 5 is positioned at distallower-right portion of the housing interior. In the bottom proximalsection is accommodated the energy supply for the actuating motors andthe other electrical parts, such as for the control and/or monitoringelements; preferably, batteries or a storage battery are used for this,e.g., a 7.2 V lithium ion battery, 1 Ah. The proximal portion of thehousing interior space above the battery compartment, is utilized mainlyfor the tension slide 28 with locking piece (FIG. 5C); this is connectedto a block 26, which is part of the base block 8. The batterycompartment is sealed on top by a separation plate.

In the upper-left part of the housing interior there is arranged abiopsy cannula carrier 37, which can be inserted into and taken out fromthe U-shaped insert holder 36 of the base block 8, which is open at thetop, and the bracket 40 arranged on either side of the tension slide 28and pointing upward; the biopsy cannula/cutting sheath unit withactuating parts is moveably mounted in this, extending for almost theentire length of the hand piece. This means that, in the uncocked state,the distal end surface of the biopsy cannula carrier 37 lies against thedistal end cover 6 of the housing, and in the cocked state the proximalend surface lies against the proximal end cover 7. “Almost the entirelength” means that the biopsy cannula carrier is at least shorter by thedistance required in the interior of the housing for the cockingsequence. If the cocking distance of the tension slide is 20 mm, forexample, the biopsy cannula carrier must be able to move by this amount.In this particular design, the cocking distance set at 20 mm. As one ofordinary skill in the art having the benefit of this disclosure wouldappreciate, the device may be adapted to allow the physician to adjustthe device to capture the desired length of the sample.

The cocking device itself consists of a tension slide 28, placed on abolt 30, the bolt screwing into the base block 8. The bolt 30 has aspiral spring 31 surrounding it. The locking device of the tension slideis secured to the block 26. In the upper-right proximal interior of thehousing is accommodated the vacuum pressure generating device 5 withparts of the actuator; the actuating motor with reduction gearing forthe vacuum pressure generating device is located in the distallower-right area of the housing interior.

At the left side of the bottom piece of the housing there is a surface113 provided for the control interface panel with the operating andmonitoring elements (FIG. 5A). The control interface panel secured tothe housing is designed as an independent component, which is glued, forexample, onto the surface 113 of the bottom piece 9. This controlinterface panel is connected by lines to other electronic componentsarranged in the housing, and to the power supply. The board contains inparticular switches for the operation and diodes for the monitoring. Theactivating button for mechanical triggering of the cocked tension slideprotrudes through a recess 65 in the bottom piece of the housing and theboard.

When configuring the operating and monitoring elements on the controlinterface panel consideration was given to the difference between thecocking sequence of the tension slide and the triggering of the tensionslide, on one hand, and the performance of the biopsy, such as thecutting out of the sample, as well as the removal of the sample with theejection of the sample, on the other hand. Accordingly, the activatingbutton (trigger) for the tension slide has been placed at the right andthe cocking button for cocking the tension slide is at left. The programbutton for performing the biopsy is in the middle. It is necessary topress the program button for three functions. The first function, startor reset, is indicated by the reset diode, while the sample removaldiode arranged underneath indicates the opening and closing of thesample removal chamber when removing the sample. The lowermost ejectdiode indicates the ejection of the removed sample. The cocking diodeindicates the cocking of the tension slide; the locking diode indicatesthe locking of the tension slide. The battery charge diode indicates thecharge condition of the battery or storage battery. The diodes areswitched so that the diode blinks while performing the particularsequence and after completion of the sequence the next diode lights up.When there are two possible choices, both diodes are lit. The operatoris then free to make a choice. The mode of operation and possibility ofcontrol shall be examined more closely in detail when describing thesequence. Symbols (icons) at the margin symbolize the individualprocesses.

To improve the operating safety it may be advisable to outfit individualautomated sequences with delay circuit. In particular, it has been foundthat the processes of “cocking of the tension slide” by pressing thecocking button and “ejection of sample” by pressing the program buttonare provided with delay circuits of around 1.2-1.5 seconds to improvethe operating safety. Furthermore, the operating safety is improved whenthe light-emitting diodes indicating the individual processes havedifferent colors for processes outside and processes inside the tissue.

A perspective representation of the base block 8 is shown in FIG. 5D.The base block 8 can be divided into two halves, looking down thelengthwise direction; the left side serves to secure the joint actuationfor cutting sheath and tension slide, and also in its upper part tomount the biopsy cannula carrier; the right side serves to secure theactuation for the vacuum pressure generating device and to mount oneside of the vacuum pressure generating device. Between the two actuatingmotors 21, 58, beneath the center rib 87, is arranged a centralelectronic system control board. The base block 8 has a U-shaped space24, in which is installed a toothed roller 23, driven by the gear motor21. For this, the take-off shaft of the gear motor is mounted orinserted in an opening in the wall 25 of the base block 8. The toothedroller 23 is mounted on the take-off shaft and secured to it, forexample, by means of a set screw, so that it cannot turn or shift. Atthe other end, the toothed roller 23 is mounted in the wall 22 of thebase block 8. The actuating motor used is a DC motor with a speed ofaround 11000 rpm. The DC motor is connected to a planet gear with highreduction ratio (e.g., 67:1), on whose take-off shaft the toothed roller23 is mounted.

An additional block 26 is machined form the wall 22, pointing in theproximal direction, which accommodates both the swiveling double lever33 for the locking process and also serves to fasten the bolt 30 forguiding the tension slide 28. The bolt 30 is screwed into the threadedborehole 29. During the cocking process, the tension slide 28 moves inthe proximal direction on the bolt 30 and the separating plate arrangedunderneath. The spiral spring 31 arranged on the threaded bolt 30 iscompressed during the cocking process. At one end, the spiral springthrusts against an end piece 32 of the threaded bolt or directly againstthe end cover 7 of the housing; the other end of the spiral springthrusts against the end of the guide borehole of the tension slide.

The tension slide 28, which adjoins the block 26, is arranged at equalheight and is roughly equal in cross section. On its top side, thetension slide has two brackets 40. The upward pointing surface 41 of thetension slide, as well as the upward pointing surface 44 of the block26, and the upward pointing surface of the extension 42 of the basicblock 8, together form a planar bearing surface for the lower slidingsurface 43 of the biopsy cannula carrier 37 mounted thereon. The biopsycannula carrier is made of plastic. As the tension slide is moved fromthe starting uncocked condition (FIG. 5E) to the cocked condition, i.e.,in the proximal direction, the biopsy cannula carrier 37 held by thebrackets 40 slides across the surface 42 and 44. It is also conceivablethat the sliding surfaces are configured not planar, as in the sampleembodiment, but instead have specially configured sliding surfaces; theimportant thing is that the biopsy cannula carrier 37 can slide easilyand straight on the sliding surface and the biopsy cannula can penetratestraight into the tissue, or tumor, after triggering the activationbutton. Therefore, the upper outer contour of the biopsy cannula carrieris also configured correspondingly to the inner contour of the housingcover and has only slight play relative to the housing cover in order toprevent the biopsy cannula from deviating upward.

FIG. 5B shows the biopsy cannula carrier 37, which can be inserted intothe brackets 40 of the tension slide 28 with biopsy cannula 2 andcutting sheath 3, as well as other parts. The hollow, round circularbiopsy cannula 2 has a needle tip, which adjoins the sample removalchamber 71 (FIG. 5F). The biopsy cannula 2, which is round in crosssection, is surrounded by a coaxially arranged cutting sheath 3, roundin cross section, having a cutting edge 72 at its distal end, facing thesample removal chamber, which serves to cut out the tissue sample afterthe biopsy cannula is introduced (with sample removal chamber closed)and after the sample removal chamber is opened and the sample is suckedinto the sample removal chamber. The cutting edge preferably standsperpendicular to the lengthwise axis of biopsy cannula and cuttingsheath. The cuffing process occurs by rotation and simultaneouslengthwise displacement of the cutting sheath by means of the threadedspindle drive. It is also contemplated that the motion occurs notcontinuously, but stepwise or vibrating, i.e., the feed process movesback and forth with short intervals. For example, the gear motor 21 isreversed for 2 mm, then reversed again for 2 mm, in a cutting motionthat is repeated again before the sample removal chamber 71 is advancedall the way forward and closed. The forward and reverse motion causesthe sharpened edge of the cannula 72 to cut the tissue while it is drawninto the sample chamber by the vacuum.

At the other, proximal end of the cutting sheath, away from the cuttingedge 72, there is fastened a threaded spindle casing 73 with a gear 74arranged at the end face of the threaded spindle casing. The threadedspindle casing with gear is arranged on the cutting sheath and preventedfrom turning and shifting. The threaded spindle cooperates with athreaded spindle nut 75, which is firmly press-fitted in the biopsycannula carrier 37. The gear 74 lies next to the nut 75, i.e., beforethe spindle casing begins. When the threaded spindle casing is turned bymeans of the gear 74, the cutting sheath is rotated and shifted inlengthwise direction along the biopsy cannula 2.

The gear 74 at the distal end of the threaded spindle engages with thetoothed roller 23 after the biopsy cannula carrier is inserted in thebrackets 40. So as to allow for inserting the biopsy cannula carrier 37into the brackets of the tension slide when the slide is not cocked(FIG. 5B), the biopsy cannula carrier has two plane parallel recesses77. When the sliding surface of the biopsy cannula carrier 37 is placedon the surfaces 41, 42 and 44, at the same time the cutting sheath isinserted in the holder 36 of the base block 8. To improve the turning ofthe spindle drive, especially when the holder 36 is used to support thecocking of the tension slide, a plastic disk 78 may be inserted at thedistal side of the gear, being provided with a slight cone. When thebiopsy cannula carrier is correctly inserted, it slides to the proximalend by the sliding surface 43 over the surfaces 42 and 41 when thetension slide is cocked. Since the specimen removal chamber is onlyclosed after inserting the biopsy cannula carrier, the gear 74 bearsagainst the holder 36. Now, if the toothed roller 23 is driven furtherin the same direction, the threaded spindle drive will screw the tensionslide in the proximal direction along the biopsy cannula carrier, untilit locks; the biopsy cannula will be pulled inward, while the cuttingsheath remains in its position. After the locking, the cutting sheathprotrudes beyond the tip of the biopsy cannula. Therefore, after thelocking of the tension slide, the cutting sheath is rotated back to thestarting position (opposite direction of rotation); the gear 74 willmove in the proximal direction in the toothed roller. After releasing ofthe tension slide, the biopsy cannula/cutting sheath with gear slidesback towards the distal direction with the biopsy cannula carrier. Now,the cutting sheath can again be moved in the proximal direction in orderto open the sample removal chamber.

The proximal end of the cutting sheath is connected to the hollow biopsycannula by a seal element 76, able to move in rotation, but air-tight,so that neither air can get in between biopsy cannula and the cuttingsheath coaxially surrounding it, nor can air escape during excesspressure. On the proximal end of the biopsy cannula 2 is mountedair-tight a round, likewise hollow plastic part 47, being frictionallyjoined to the biopsy cannula. The plastic part 47 has a bearing element49 at its distal end, which is press-fitted into the biopsy cannulacarrier; at its proximal end, protruding from the hand piece 1, there isinserted another plastic part 112, which can turn relative to theplastic part 47 and the biopsy cannula 2. Between biopsy cannula andplastic part 112 there is inserted an O-ring seal. The plastic part hasa plug 17 at its proximal end, onto which the connection element 4 isplaced air-tight.

There is also a knurled disk 80 on the proximal end, protruding from thebiopsy cannula carrier and the housing, by which, when rotated, theposition of the sample removal chamber can be adjusted radially, withoutaltering the position of the cutting sheath. One rotation of the biopsycannula involves only one rotation of the sample removal chamber and,thus, the sample removal device. The plastic part 47 with biopsy cannulaand cutting sheath is press-fitted into the biopsy cannula carrier withthe bearing element 49 and the threaded spindle nut 75. The biopsycannula can rotate in the biopsy cannula carrier and is mounted in thecutting sheath by the bearing element 49 and its narrow guide in thecutting sheath, and it can shift in the lengthwise axis with the biopsycannula carrier. As described above, the cutting sheath is axiallymovable by rotation relative to the biopsy cannula. A polygon 50(positioned proximal of the bearing element 49) is arranged on theplastic part, which can lock with the biopsy cannula carrier by tension,so that the sample removal chamber of the biopsy cannula can be broughtinto the most favorable position for the biopsy removal and held thereby means of the knurled disk 80.

Details of the sample removal chamber and the tip of the biopsy cannulaare represented in FIG. 5F. The sample removal chamber 71 adjoining theneedle tip is open above for approximately 25% of its cross section. Thecutting edges, including the distal circumference of the cutting sheath3 and the sides of the sample removal chamber 72 on the biopsy cannula,may be grounded or sharpened. The sample removal chamber is betweenapproximately 15 and 25 mm in length. It adjoins the cavity of thebiopsy cannula. At the transition, i.e., the proximal end of the sampleremoval chamber, the cross section of the cavity of the biopsy cannulais closed between approximately 50% and 75% by a narrowing, e.g., astopper 79. The height of the stopper is chosen such that it extendsdownward past the recess of the sample removal chamber. In this way, thevacuum will especially draw in the tissue sample through the continuousopening of the sample removal chamber and bring the tissue sample upagainst the wall of the sample removal chamber.

When there is excess pressure in the cavity of the biopsy cannula, thenarrowing or stopper has a pressure boosting effect. The stopper hasroughly the length of 10 mm and is glued or welded into the cavity. Whenusing laser welding, it has proven to be advantageous to make the distalside of the stopper thin for a short length, around 2 mm, by removingmaterial at the end surface. As a result, in this region at the endsurface the tube of the biopsy cannula is welded to the end surface ofthe stopper and is air-tight at the end surface. The stopper can also beof shorter length, as long as the same effect is achieved. Thus, thestopper can also be replaced by a lip or a partial plug of approximatelythe same height. The important thing is that the narrowing is configuredsuch that the vacuum is brought to bear primarily from the bottom in thesample removal chamber, so that the sample clings to the wall of thesample removal chamber during the cutting process and does not change inlength. It has also proven to be advantageous to provide additionalfixation means on the sample removal wall.

The suctioning of the sample from the bottom into the sample removalchamber produces, first, a high fill ratio of the sample removal chamberand, second, especially due to its configuration, a good fixation of thesample on the wall. Since the cutting sheath separates the sample at theoutside of the biopsy cannula, this firm suctioning of the sample intothe interior is also preserved during the separation process.Furthermore, due to the cutting sheath arranged on the outside, and thevacuum applied, no tissue is suctioned into the hollow cutting sheathand thus the tissue cannot get twisted or turned by the rotatinglengthwise movement of the cutting sheath, as it is held fast in theinterior of the cutting sheath. This improves the quality of the sample,since the pathologist obtains original material corresponding to thecross section of the cut and not being twisted or deformed. When thesample is ejected under pressure, a complete cleaning of the sampleremoval chamber occurs in addition through the stopper 79, so that nocommingling occurs when used repeatedly. Since the vacuum generatingdevice is used at the same time as a pressure generating device, theentire cavity is cleaned, especially that of the cannula.

FIG. 5H shows the drive and the installation of the vacuum pressuregenerating device 5 (view from the rear, i.e., opposite the Z-axis,housing cover and lower housing piece left out). In the upper-rightproximal region, the vacuum pressure generating device 5 is arranged asa piston/cylinder unit 69. It consists of a syringe body 52 withthreaded spindle 53 arranged inside, at whose end facing the syringebottom there is fastened a plunger with seal elements—as is commonlyknown with syringes. At the end of the syringe body 52 facing the baseblock 8, a threaded spindle nut is arranged on the threaded spindle witha gear 55 formed at the circumference. The threaded spindle nut has oneor more thread turns. The threaded spindle 53 interacts with thethreaded spindle nut. The spindle has a pitch of around 5 mm per turn,so that at each rotation the plunger is moved out from the syringe bodyby a precisely defined amount, i.e., away from the syringe bottom, ortoward the syringe bottom, depending on the direction of turning.

The toothed crown 55 arranged on the circumference of the threadedspindle nut meshes with the drive pinion 56, which is fastened on thetake-off shaft of the DC gear motor 58. The take-off shaft of the DCgear motor 58 is mounted in the base block 8; for this, the take-offshaft is inserted into the transverse plate 59 of the base block. Whenthe DC gear motor 58 is activated, the plunger is moved toward thesyringe bottom or in the direction of the base block 8, depending on thedirection of turning. The drive motor used is likewise a DC motor withhigh speed, connected to a planet transmission with high reductionratio. It corresponds to the motor already described for the cockingmechanism.

The plunger is configured in familiar fashion as a syringe plunger. Thesyringe body made from plastic, being a cylinder with a bottom, istransparent. In order to prevent a twisting of the threaded spindle 53upon actuation of the threaded spindle nut, the two opposite surfaces ofthe threaded spindle are plane in configuration. The threaded spindle isinserted into the insert element by its free end. The spacing betweenthe surfaces of the threaded spindle corresponds to the width of theU-shaped insert element of the base block 8. There is only slight playbetween the U-shaped cross section of the insert element and the spindlesurfaces at either end. The threaded spindle nut thrusts against thebase block. In order to prevent the syringe body from sliding out uponturning of the threaded spindle nut, the bearing surface at the baseblock 8 is slightly conical toward the bottom. The connection piece ofthe syringe body is inserted into the passage 16 of the proximal endcover 7 so that the syringe body is held in roughly horizontal position.In addition, a pin pressed into the machined aluminum motor block mayalso be provided to prevent the syringe from rotating. The pin restsagainst the plastic syringe body when the needle is loaded into thehousing properly. When the lid is closed the pin digs into the syringeslightly and prevents the syringe from rotating.

If the syringe plunger is moved beyond the ventilation opening 67 (FIG.5H)—when the vacuum is no longer required—intake of air (atmosphericpressure) through the ventilation opening 67 will dissipate thepreviously established vacuum in the hollow biopsy cannula. If, then,the direction of turning of the gear motor is reversed, the vacuumpressure generating device will build up an excess pressure in thesystem by retraction of the plunger (toward the bottom of the syringe),which brings about the ejection of the tissue sample after opening thesample removal chamber. Moreover, the pressurized air will clean notonly the sample removal chamber, but also in particular the inside ofthe biopsy cannula. The stopper narrowing the cavity of the cannula willmake it difficult or entirely prevent tissue parts from getting into thecavity of the biopsy cannula. The narrowing of the cannula cavity by thestopper 79 will increase the pressure at the sample removal chamber andthereby improve the ejection of the sample, even when the sample removalchamber is half open.

This invention has been described and specific examples of the inventionhave been portrayed. While the invention has been described in terms ofparticular variations and illustrative figures, those of ordinary skillin the art will recognize that the invention is not limited to thevariations or figures described. In addition, where methods and stepsdescribed above indicate certain events occurring in certain order,those of ordinary skill in the art will recognize that the ordering ofcertain steps may be modified and that such modifications are inaccordance with the variations of the invention. Additionally, certainof the steps may be performed concurrently in a parallel process whenpossible, as well as performed sequentially as described above.Therefore, to the extent there are variations of the invention, whichare within the spirit of the disclosure or equivalent to the inventionsfound in the claims, it is the intent that this patent will cover thosevariations as well. Finally, all publications and patent applicationscited in this specification are herein incorporated by reference intheir entirety as if each individual publication or patent applicationwere specifically and individually put forth herein.

1. A biopsy device, comprising: a biopsy cannula having a longitudinalaxis, a lumen with a lumen wall, distal and proximal ends, and a samplechamber at the distal end of the biopsy cannula; an access openinglocated at a circumferential surface of the biopsy cannula providingaccess to the sample chamber, the access opening facing radially awayfrom the longitudinal axis and the sample chamber having a blind endopposite the access opening formed by a portion of the lumen wall of thebiopsy cannula to define a bottom of the sample chamber; a narrowingdevice positioned in the lumen of the biopsy cannula at a proximal endof the sample chamber to define a restriction in the lumen and an openarea in the lumen, wherein a cross section of the open area between thenarrowing device and the biopsy cannula at the restriction is less than50 percent but greater than zero percent of a cross section of the lumenof the biopsy cannula, the open area being located to communicate withthe sample chamber, the open area being positioned proximal to theaccess opening and at an opposite side of the lumen relative to theaccess opening at the blind end of the sample chamber; a retractablesheath disposed to be movable relative to the sample opening; and avacuum source coupled in fluid communication with the lumen of thebiopsy cannula for selectively supplying vacuum to the sample chambervia the open area at the restriction such that vacuum when applied willbe brought to bear from the bottom of the sample chamber.
 2. The deviceof claim 1, further comprising a controller configured to drive anoperating sequence in which air is pumped into the sample chamber, thesample chamber is then uncovered by the covering sheath to cause air toexpel a sample therein.
 3. The device of claim 1, wherein the narrowingdevice defines a wall portion at the proximal end of the sample chamberto which a tissue sample will cling when vacuum is applied to the lumenduring a cutting process, and wherein a cross section of the lumen ofthe biopsy cannula is closed between approximately 50 percent and 75percent by the narrowing device, and the opening is formed as a singleaperture.
 4. The device of claim 1, further comprising a controllerconfigured to drive an operating sequence in which air is pumped intothe sample chamber, the sample chamber is then uncovered by the coveringsheath to cause air to expel a sample therein.
 5. The device of claim 1,wherein the retractable sheath includes a cutting sheath that is axiallymovable relative to the biopsy cannula and surrounds the biopsy cannula,the cutting sheath having a distal cutting surface.
 6. The device ofclaim 1, further comprising a controller configured to drive anoperating sequence in which air is pumped into the sample chamber, thesample chamber is then uncovered by the covering sheath to cause air toexpel a sample therein.
 7. The device of claim 1, wherein the sheathincludes a cutting sheath that is axially movable relative to the styletand surrounds the stylet, the cutting sheath having a distal cuttingedge; a drive configured to simultaneously rotate the cutting sheathwhile translating it from a proximal position, where the cutting edge ison a proximal end of the sample chamber access opening, toward thedistal end, such that the cutting sheath covers the sample chamberaccess.
 8. The biopsy device of claim 1, wherein the sample chamber isopen above the portion of the lumen wall for approximately 25 percent ofthe cross section of the lumen of the biopsy cannula to form the accessopening.
 9. A biopsy device, comprising: a biopsy cannula having alongitudinal axis, a lumen with a lumen wall, distal and proximal ends,and a sample chamber at the distal end of the biopsy cannula; an accessopening located at a circumferential surface of the biopsy cannulaproviding access to the sample chamber, the access opening facingradially away from the longitudinal axis and the sample chamber having ablind end opposite the access opening formed by a portion of the lumenwall of the biopsy cannula to define a bottom of the sample chamber; anarrowing device located at a proximal end of the sample chamber todefine a transition between the lumen and the sample chamber along thelongitudinal axis, and an open area that bypasses the narrowing deviceto provide a fluid passage between the sample chamber and the lumen, theopen area being positioned proximal to the access opening and at anopposite side of the longitudinal axis relative to the access openingsuch that the open area is adjacent the bottom of the sample chamber; aretractable sheath that is selectively movable relative to the accessopening; and a vacuum source coupled in fluid communication with thelumen of the biopsy cannula.
 10. The device of claim 9, furthercomprising a controller configured to drive an operating sequence inwhich air is pumped into the sample chamber, the sample chamber is thenuncovered by the covering sheath to cause air to expel a sample therein.11. The device of claim 9, wherein a cross section of the open area isless than 50 percent but greater than zero percent of a cross section ofthe lumen of the biopsy device, the open area being a single aperture.12. The device of claim 11, further comprising a controller configuredto drive an operating sequence in which air is pumped into the samplechamber, the sample chamber is then uncovered by the covering sheath tocause air to expel a sample therein.
 13. The device of claim 9, whereinthe retractable sheath includes a cutting sheath that is axially movablerelative to the biopsy cannula and surrounds the biopsy cannula, thecutting sheath having a distal cutting surface.
 14. The device of claim13, further comprising a controller configured to drive an operatingsequence in which air is pumped into the sample chamber, the samplechamber is then uncovered by the covering sheath to cause air to expel asample therein.
 15. The device of claim 9, wherein the sheath includes acutting sheath that is axially movable relative to the stylet andsurrounds the stylet, the cutting sheath having a distal cutting edge; adrive configured to simultaneously rotate the cutting sheath whiletranslating it from a proximal position where the cutting edge is on aproximal end of the sample chamber access opening toward the distal endsuch that it covers the sample chamber access.
 16. The biopsy device ofclaim 9, wherein the sample chamber is open above the portion of thelumen wall for approximately 25 percent of the cross section of thelumen of the biopsy cannula to form the access opening.